Solid state lighting systems including LEDs generally have one or more LED dice inside an LED package, which is assembled onto a printed circuit board (PCB), sometimes in combination with an electrical driver that can be either co-located or separately connected. The LED-containing PCB is combined with one or more secondary optic(s), placed in a bulb, and assembled into a lamp. The multiple layers of packaging, including for example the LED package, the PCB, the secondary optics, the bulb, and the lamp, increase the size, the cost, and the complexity of manufacturing the lamp. Also, multiple layers of packaging may reduce light extraction from the lamp, as light has to be extracted from each of the layers of packaging, and each layer of packaging generally absorbs some light. These same multiple layers of packaging may also reduce the efficiency of heat extraction from the LEDs thus further reducing their optical efficiency.
Semiconductor light-emitting devices including light emitting diodes (LEDs), resonant cavity light emitting diodes (RCLEDs), vertical cavity laser diodes (VCSELs), and edge emitting lasers are among the most efficient light sources currently available. Materials systems currently of interest in the manufacture of high-brightness light emitting devices capable of operation across the visible spectrum include Group III-V semiconductors, particularly binary, ternary, and quaternary alloys of gallium, aluminum, indium, and nitrogen and/or phosphorus. Typically, III-V light emitting devices are fabricated by epitaxially growing a stack of semiconductor layers of different compositions and dopant concentrations on a sapphire, silicon carbide, silicon, III-nitride, GaAs or other suitable substrate by metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or other epitaxial techniques. The stack often includes one or more n-type layers doped with, for example, Si, formed over the substrate, one or more light emitting layers in an active region formed over the n-type layer or layers, and one or more p-type layers doped with, for example, Mg, formed over the active region. Electrical contacts are formed on the n- and p-type regions.